DE29818075U1 - Fluid actuator - Google Patents

Description

Kuhnke GmbH
Lütjenburgerstrasse 101
23714 Malente

Fluidic actuator

The invention is based on a fluidic actuator, consisting of a housing which is provided with an at least partial recess, with a piston which is movable in the recess by fluid pressure and which releases a pressure force under the influence of fluid pressure, which divides the recess into two variable fluid pressure chambers which are separated from one another in a fluid-tight manner and which is provided with a force tapping device, furthermore with a cover which closes the housing in a fluid-tight manner on at least one side, furthermore consisting of a control which is structurally assigned to the actuator and which is preferably combined into a structural unit.

Such actuators are generally known in fluid technology and are used for translational movements or angle-limited swivel movements while delivering corresponding forces or torques, among other things in machine and device construction. The actuators in question have a hollow cylindrical housing, which has a piston that is guided in a sealed manner and can be moved translationally or swiveled at a limited angle.

which is provided with a force pickup device, e.g. a piston rod or pickup shaft.

Fluidic actuators are known that are directly and immediately equipped with appropriately controllable valves, e.g. solenoid valves. Such actuators are preferably used in hydraulic applications.

Furthermore, fluidic actuators are known which are provided with signaling means to detect the respective piston position. These signaling means can, if required, be designed in such a way that piston positions are queried over the entire possible movement path of the piston, or the signaling means are attached at a defined location within the movement path and thus detect when the piston is reached or overtraveled at this location.

Depending on the design of these signaling devices, the detected signals are electronically amplified directly within the signaling device and made available to other higher-level controls, whereby the signaling device and the electronic amplification are often combined in one unit.

A disadvantage of the known fluidic actuators, hereinafter referred to as actuators, is on the one hand the high level of fluidic installation work required, which begins with supplying the fluid to each valve being controlled. The fluidic connection of the valve then requires the corresponding connection to the actuator. Another disadvantage is that such an installation requires a large amount of structural space.

Another disadvantage is that a very complex installation is also required for signal processing. Primarily due to the increasing use of electronic signal processing, the installation of the corresponding converters, e.g. the effort required to electrically connect solenoid valves with an increasing number of actuators in a system, is also becoming increasingly larger and more confusing. This begins with the design and creation of a corresponding device-related circuit diagram, which is derived from a control flow chart. At the same time, due to the large number of possible connection variants, there is also a correspondingly high probability of errors during installation.

The invention is therefore based on the object of creating a fluidic actuator which, on the one hand, is small, inexpensive and reliable, and on the other hand, reduces the fluidic and control technology as well as the installation effort to a minimum.

This task is solved by the fact that the control assigned to the actuator includes:

- an electronic control system with signal inputs and signal outputs, whereby the electronic control system detects and evaluates signals related to it and passes them on to a converter based on the specifications,

- a fluidic supply connection for the pressure medium application to the respective fluid pressure chambers, which can be influenced by the control system,

- at least one converter that converts the electrical signals evaluated by the electronic control system and thus available to the converter into adequate fluidic signals,

- fluidic connecting means through which the fluidic signals released by the converter are fed to the respective fluid pressure chamber as pressure fluid or, coming from the pressurized fluid pressure chamber, are fed to a pressure relief device.

In this case, an electronic control is a component of the control system assigned to the actuator, which in its entirety therefore consists of the electronic control system together with signal inputs and outputs, and also of a converter that converts the electrical signals provided by the electronic control system into appropriate fluid signals, with the converter in turn being assigned a fluidic supply connection. The fluidic signals output by the converter are fed to the fluid pressure chambers via fluidic connecting means. The fluid pressure chambers in turn are formed from the recess in the housing and the piston that can be moved therein, which divides the recess into two variable fluid pressure chambers.

The electronic control can be designed, for example, in such a way that it is provided with signal input means, storage and/or computing means, program input and processing means and signal output means and that these are linked to one another in such a way that the electronic control is able to independently execute its own, predefined program. On the other hand, it is also possible to design and implement the electronic control in such a way that it is, for example, bus-compatible, has additional signal inputs and acts as a decentralized control with the actuator as a structural unit in the function of a slave, which is controlled by a hierarchically higher-level

can be controlled by a master control system. This master can, for example, send out signals according to a defined bus protocol, which are fed to several similar electronic controls at the same time. Each of these electronic controls obeys a defined, previously determined code, in which this signal is recognized, evaluated and passed on to the converter. The converter is activated accordingly and switches the pressure fluid into the respective fluid pressure chamber of the actuator. Depending on the pressure difference in the fluid pressure chambers, which are separated by the movable piston, a piston movement and/or a corresponding force or torque output at the force tapping device now takes place. This force tapping device can, for example, be the piston rod on an actuator designed as a cylinder-piston unit with a piston rod. In an actuator that carries out a swivel movement with a limited angle, the force tapping device is usually a shaft that transmits the torque.

The control is combined into a single unit in a housing that simultaneously has connection means for input signals and a converter with associated fluid connection.

The control is connected to the cover and/or the housing in a fluid-tight manner via fluidic connecting means. In another embodiment, at least a part of the control or the converter is integrated into the cover or the housing. Such a housing can, for example, be designed for a cylinder-piston unit as a deep-drawn sleeve, the closed bottom side of which is dimensioned such that parts of the converter can be inserted into it. This can be done in the axial direction or transversely to the axial direction, depending on the object. The housing of an actuator that carries out an angle-limited swivel movement is preferably a pressed

or cast or injected molded part. However, this molded part can also be manufactured using other manufacturing processes, e.g. mechanical machining.

The converter is designed as an electrically controllable multi-way valve, e.g. as a 3/2-way solenoid valve, - or in the case of a double-acting valve as a 4/2- or 5/2-way valve. It is also possible to assign two open/close valves (2/2-way valves) as converters to each of the fluid pressure chambers of the actuator, whereby each fluid pressure chamber contains a valve for the fluid supply or shut-off and another valve for pressure relief for each fluid pressure chamber. In a supplementary design, the actuator is provided with means by which the speed of the piston movement can be influenced. Such means can be throttle valves or orifices, which can be set to a certain speed by hand, for example. In a further design, however, these means for changing the speed can also be controlled electrically, e.g. B. controlled by an electric motor, so that signals from the electronic control system influence the respective speed in accordance with the specification.

In another version, the converters can be controlled electrically, e.g. pulse width modulated. This also allows the speed of the piston movement to be influenced. The cycle sequence can be specified depending on the program and can even be changed during a piston movement. The time of the pressure fluid supply and/or the time of the pressure relief can be influenced as required.

In a further embodiment, the housing is provided with additional recesses which can be used, for example, to accommodate signaling devices. These signaling devices detect, for example, the piston movement or the location of the piston and the signals are fed into the electronic control system

These signals can either be further processed within the control system according to a specified program or made available to an upstream, hierarchically higher master for further evaluation via a signal transmission device. It is of course also possible to equip the actuator with a signal transmitter that continuously detects the piston position over the entire possible range of movement of the piston.

The control system is equipped with an additional extension with lamps for status display, so that the lamps can be used to identify, for example, which fluid pressure chamber is currently pressurized or depressurized. To further clarify this feature, the lamps can be made in different colors, e.g. red and green, with each color being assigned to a corresponding switching state.

In yet another variant, the electronic control and/or lighting devices are directly assigned to the converter. This can mean, for example, that a solenoid valve assigned to the actuator is provided with a corresponding electronic control and/or lighting devices in the area of the coil. - In a modification of this embodiment, it is also possible to integrate the electronic control with the respective signal input and the corresponding power supply into an electrical connector plug that is plugged into the electrical connections of the assigned solenoid valve, whereby the said connector, the converter and the actuator form a common structural unit.

Further advantageous design options can be found in the subclaims.

The actuator is explained below using the drawing as an example. Shown are:

Figure 1 shows a perspective view of an actuator designed as a cylinder-piston unit in a first design variant,

Figure 2 shows a partial section through the housing of the actuator designed as a cylinder-piston unit and the assembly unit that has not yet been assembled.

Figure 3 shows a perspective view of the actuator designed as a cylinder-piston unit, with the control system open.

Figure 4 shows a perspective view of the actuator designed as a cylinder-piston unit with an associated signal generator.

In Figure 1, the actuator is shown as a cylinder-piston unit 1, which consists of the housing 2, the front covers 11, 12, the cover fastening means 4.5 to 4.8, the force pickup device, which in this case is a piston rod 10, and the structural unit 14. The structural unit in turn consists of the control 13, which is provided with the connection means 16, 16.0 for the signal inputs 16.1, 16.2 and with the fluidic supply connection 17. The structural unit 14 is firmly connected to the cover 11 or the housing 2 in a fluid-tight manner to form a unit 1.

Figure 2 shows an example of a partial section through the housing 2, which is provided with a recess 3 parallel to the longitudinal axis X-X, in which a piston 7 is inserted in a fluid-tight manner, in this example movable in translation. This piston 7 separates the recess 3 into a variable fluid pressure chamber 8 and 9. On the side of the fluid pressure chamber 9, the

Piston 7 is provided with a piston rod 10 as a force tapping device, which penetrates the cover 12 in a fluid-tight manner to the outside, i.e. to the atmosphere. This piston rod 10 serves to tap the translatory movement and the force tapping. The cover 11 is provided with a fluidic connecting means 19.3, 19.4, of which one connecting means is assigned to each of the fluid pressure chambers 8 and 9, respectively, which is not shown in the drawing. These fluidic connecting means 19.3, 19.4 also correspond to fluidic connecting means 19.1, 19.2, which are assigned to the cover 11 from the control 13 in the ready-to-use state. The fluidic supply connection 17 corresponds to a fluidic input of the converter 18 (not shown in the drawing) - Figure 3. According to the respective electrical input signals, the fluid inflow through the converter 18 is influenced in such a way that either fluid pressure is fed via the fluidic connecting means 19.1 into the fluidic connecting means 19.3 of a first fluid pressure chamber while the other fluid pressure chamber is subjected to pressure relief via the fluidic connecting means 19.4, 19.2.

Figure 3 shows the opened control system, which consists of assembly 13.1 and assembly 13.2. Assembly 13.1 includes, among other things, the fluid supply connection 17 and the converter 18 and means 20 for influencing the speed of the piston. In this example shown, these means 20 can be operated manually.

The assembly 13.2 shows the electronic control 15, which is supplied with corresponding control signals via the signal inputs 16.1,16.2 and through which the supply voltage for the electronic control 15 and the converter 18 is supplied.

When the modules 13.1 and 13.2 are assembled, electrical contact means 25 supply the converter 18 with the corresponding electrical control signals and the supply voltage via contact means 25.1. Additional contact means 26.1 can be assigned, for example, to a signal generator means 30 (see Fig. 4), the signals of which are fed to the electronic control 15 via contact means 26. In this case, the electronic control 15 can use the signals from the signal generator means 30 either directly for further processing, or make them available to a hierarchically higher-level master control after further internal processing has taken place. The signal flow direction can therefore also be designed to be bidirectional.

For example, the controller 15 can contain a counting stage so that only every nth signal is made available to a hierarchically higher master controller as an acknowledgement signal while the counting process runs internally in the controller 15.

In Figure 4, the housing 2 is provided with two recesses 6.1, 6.2 for accommodating, for example, signaling means 30. The cover 12, through which the piston rod 10 penetrates in a fluid-tight manner, is not mounted on the housing 2 in the illustration, in order to make the recesses 6.1 and 6.2 more clearly visible, but also to show the fluidic connecting means 5, which is used to convey the pressure fluid. In this example, this connecting means 5 is formed as an axially parallel recess in the housing 2 and is assigned to the variable fluid pressure chamber 9. In the operational state, the cover 12 is connected to the housing 2 in a fluid-tight manner by cover fastening means 4.6 to 4.8. These fastening means 4.6 to 4.8 can be, for example, screws that interact with corresponding internal threads 4.1 to 4.4 within the housing 2.

·

The signal generator means 30, which is arranged in the recess 6.1, can be moved axially within this recess and can be firmly positioned at any location within the possible movement range of the piston by means of fastening means, e.g. a fastening screw. The signals coming from the signal generator means 30 can, as already described by way of example, be processed directly within the structural unit 14 by the electronic control 15.

This invention also enables an actuator as a piston rodless cylinder. The power transmission of the piston, which can be moved translationally by fluid pressure, can be carried out, for example, by a cable pull with pulleys, to an axially movable force pickup device, for example, assigned to the outside of the housing. Another possibility is the contactless power transmission from the piston to the force pickup device. In this case, there is a permanent magnetic coupling between the piston, which can be moved translationally in the housing by fluid pressure, and a force pickup device outside the housing, e.g. on the latter, which can be moved translationally. Piston rodless cylinders can also be provided with signaling means in the manner described.

In a similar way, actuators with angle-limited swivel movement can be combined with the electronic control and signaling means to form a structural unit. A more detailed discussion of this is unnecessary, since, based on the previous description, a person skilled in the art is familiar with the corresponding design of rodless cylinders and actuators that perform swivel movements.

The advantages of the fluidic actuator according to the invention lie first of all in the simple solution of the task-related control design

embedding, &zgr;. B. by writing a program into the electronic control, furthermore in the simplified fluidic installation, as well as in the simplified supply of the control signals. These advantages of the signal supply are particularly noticeable when the actuator is designed to be bus-compatible. By designing the electronic control accordingly, the actuator can be given its own sub-program, so that this can be referred to as "decentralized intelligence on site". With a small control scope, the actuator itself can therefore process its own program directly. - With more complex control tasks, the actuator can be assigned as a slave to a hierarchically higher-level master control, whereby the slave is also able to provide the master with acknowledgement signals.

This innovation also has an advantageous effect in terms of the maximum achievable speeds of the piston, as the shortest possible and flow-optimized connections from the converter to the respective fluid pressure chambers are integrated into the actuator.

Claims (23)

Protection claims 1. Fluidic actuator, consisting of a housing which is provided with an at least partial recess, with a piston which is movable in the recess by fluid pressure and releases a pressure force under the influence of fluid pressure, which divides the recess into two variable fluid pressure chambers separated from one another in a fluid-tight manner and which is provided with a force tapping device, furthermore with a cover which closes the housing in a fluid-tight manner on at least one side, furthermore consisting of a control which is structurally assigned to the actuator and which is preferably combined to form a structural unit, characterized in that the control (13) contains: an electronic control (15) with signal inputs and signal outputs (16.1,16.2), whereby the electronic control (15) recognizes signals related to it, evaluates them and forwards them to a converter (18) in accordance with the specifications, a fluidic supply connection (17) for the pressure medium applied to the respective fluid pressure chambers (8, 9) that can be influenced by the control (13), at least one converter (18) which converts the electrical signals evaluated by the electronic control (15) and thus available to the converter (18) into adequate fluidic signals, -14-&idigr;&idigr;&iacgr;&idigr; ·* ! &igr;&ggr;;*&phgr;.· fluidic connecting means (19.1,19.2) through which the fluidic signals released by the converter (18) are supplied to the respective fluid pressure chamber (8, 9) as pressure fluid, or are supplied to a pressure relief device coming from the pressurized fluid pressure chamber (8, 9). 2. Actuator according to claim 1, characterized in that the structural unit (14) is connected in a fluid-tight manner to the cover (11, 12) and/or to the housing (2). 3. Actuator according to claim 1, characterized in that the control (13) is at least partially integrated into the cover (11, 12) and/or into the housing (2) on the side inclined towards the cover (11, 12). 4. Actuator according to claim 1, characterized in that the converter (18) and/or the fluidic connecting means (19.1 to 19.4) is/are at least partially integrated into the cover (11, 12) and/or the housing (2). 5. Actuator according to one of the preceding claims, characterized in that the converter 18 is an electrically controllable multi-way valve. 6. Actuator according to one of the preceding claims, characterized in that two open/close valves are assigned as converters to each fluid pressure chamber (8, 9) separated by the piston (7), of which one valve influences the pressure fluid supply or shut-off for each fluid pressure chamber (8, 9) and a further valve effects the pressure relief for each fluid pressure chamber (8, 9). 7. Actuator according to one of the preceding claims, characterized in that the actuator has means whereby the duration of the pressure fluid supply and/or the pressure relief of the respective fluid pressure chamber (8, 9) can be influenced in time. 8. Actuator according to one of the preceding claims, characterized in that the pressure fluid supply or shut-off, or the pressure relief associated converter from the electronic control (15) can be controlled in a clocked manner. 9. Actuator according to one of the preceding claims, characterized in that a throttle or orifice or a throttle check valve is used to influence the timing of the pressure fluid supply and/or the pressure relief. 10. Actuator according to claim 9, characterized in that the throttle or orifice or the throttle check valve has an adjustment option (20). 11. Actuator according to claim 10, characterized in that the adjustment option (20) is electrically controllable. 12. Actuator according to claim 11, characterized in that control signals for the electrical adjustment option (20) come from the electronic control (15). 13. Actuator according to one of the preceding claims, characterized in that the actuator (1) has at least one signal generator means (30) which detects the movement or the location of the piston (7) or the force pickup device (10) and feeds corresponding signals into the control (15). 14. Actuator according to claim 13, characterized in that the signal generator means (30) is adjustable on the housing (2). 15. Actuator according to one of the preceding claims, characterized in that the control (13) has lighting means (40) for status display. 16. Actuator according to one of the preceding claims, characterized in that the electronic control (15) is an integral part of the converter (18). 17. Actuator according to claim 16, characterized in that the converter (18) has lighting means (40) for status display. 18. Actuator according to one of the preceding claims, characterized in that the converter (18) has means whereby the duration of the pressure fluid supply and/or the pressure relief of the respective fluid pressure chamber (8, 9) can be influenced in time. 19. Actuator according to one of the preceding claims, characterized in that the electronic control (15) has signal input means, storage and/or computing means, program input and processing means and signal output means and that these are interconnected are linked in such a way that the electronic control (15) independently executes a predetermined program. 20. Actuator according to claim 19, characterized in that the electronic control (15) is bus-compatible. 21. Actuator according to claims 19 and 20, characterized in that the electronic control (15) has additional signal inputs. 22. Actuator according to claims 19 to 21, characterized in that the electronic control works as a slave with a hierarchically higher-level electronic control to process the program. 23. Actuator according to one of the preceding claims 19 to 22, characterized in that the electronic control (15) is accessible to bidirectional data exchange and processing.